Airbag arrangement

ABSTRACT

An improved airbag arrangement in motor vehicles is described having at least one gas generator, a generator carrier, a folded together gas bag having at least one opening which receives the gas generator and a pot-like cover which accommodates the folded together gas bag, with the base of the pot-like cover being capable of being broken open by means of the gas bag expanded by the gas generator and with the marginal region of the cover remote from the base being connected to the generator carrier.

BACKGROUND OF THE INVENTION

The invention relates to an airbag arrangement in accordance with thepreamble of claim 1.

In the case of accident-dependent accelerations of the vehicle intowhich the airbag arrangement is built a pyrotechnical charge in the gasgenerator ignites and causes hot gases which emerge from preferablyradial bores provided there to flow into the folded up gas bag, whichthen inflates while breaking open the cover and protects the vehicleoccupant from too hard an impact.

With known arrangements of this kind (EP 0 376 564 A1, DE 42 05 726 A1)the problem exists that a relatively large number of individual parts isnecessary and the assembly requires such a large effort that aneconomical manufacture, in particular in mass production, is notpossible. Furthermore, the gas bag must be provided with a bead at theopening. This is also the case with a gas sack in accordance with DE 9014 749 U.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an airbag arrangementof the initially named kind which consists of as few individual parts aspossible and which can be manufactured and installed in a particularlyeconomical manner.

The features of the characterising part of claim 1 are provided in orderto satisfy this object.

The concept underlying the invention is thus to be seen in clamping themarginal region of the gas bag at the opening between two arealcomponents extending all around the opening which are in any eventpresent, or which can be additionally provided without particularexpense or complexity.

The possible design in which the marginal region of the gas bag at theopening is clamped between the inner wall of the marginal region of thecover and a wall part of the generator carrier which extends at leastsubstantially parallel to the inner wall, enables particularly simplemanufacture. For this the folded together gas bag which ispremanufactured, for example in a low labour-cost country, is simplylaid into the pot-like cover with the marginal region at the openingcoming into contact with the marginal region of the cover. The generatorcarrier which carries the generator now only needs to be insertedaxially whereupon, as a result of suitable dimensioning of theindividual components, the sealed connection of the marginal region ofthe gas bag at the opening with the components surrounding it hasalready been largely completed. This clamping can subsequently befurther reinforced by fastening means or retained in the existing form.The marginal region of the gas bag at the opening thus represents a typeof collar which cooperates with the collar-shaped regions complementarythereto, namely the marginal region of the cover and the wall part, toform a sealed connection. In this arrangement the separatepremanufacture of the gas bag and the manufacture and joining togetherof the high value parts in a workshop equipped with high valuemanufacturing tools enables particularly favourable manufacture.

With a circularly symmetrical design of the airbag arrangement the wallpart, the marginal region at the opening and the marginal region of thecover represent right cylinders or cones which taper slightly in thedirection of the base. The cross-section of the arrangement can howeverbasically be selected as desired, i.e. can also be rectangular orsquare. Moreover, instead of only one gas generator several gasgenerators can also be provided at the generator carrier.

The embodiment of claim 2 is particularly advantageous since the layingof the end region of the marginal region at the opening around the endedge of the marginal region of the cover facilitates the axial insertionof the generator carrier during installation and the danger of themarginal region at the opening being displaced on insertion of thegenerator carrier is avoided.

A particularly advantageous fastening method is the use of fastenerclips distributed around the circumference because the fastener clipscan be provided in one piece with the generator carrier duringmanufacture thereof. The assembly of the wall part of the generatorcarrier, of the marginal region of the gas sack at the opening and ofthe marginal region of the cover can be improved by fastening bores.Particularly advantageous is a design which ensures a connection of theindividual parts in a single riveting step.

The preferred frame-like design of the generator carrier has theadvantage that, by suitable dimensioning of the frame width, the spacingof the hot gas outlet bores of the gas generator from the radiallyoppositely disposed marginal region at the opening can be selected insuch a way that, on triggering of the gas generator, the hot outflowinggases cannot damage the gas bag in the marginal region at the opening.

The provision of a step in the frame part is particularly advantageoussince in this way the hot gas jets from the gas generator primarilyimpinge onto the step which in particular extends obliquely and areaxially deflected in the direction towards the gas bag as a result of asuitable inclined position of the step, so that only regions of the gasbag are struck by the hot gas which are being blown up rapidly and arethus being removed relatively quickly from the hot gas flux.

The design of claim 7 makes particularly favourable production possiblewith a secure installation also being ensured.

The arrangement in accordance with which the frame part is formed as anat least substantially planar plate with an opening for receiving thegenerator and is connected to the end of the wall part remote from thebase of the cover, with the marginal region at the opening which isdirected there being clamped between the plate and a preferably planarcover pan having an opening for receiving the generator and arranged atthe side of the plate remote from the base of the cover and ispreferably connected to the plate by fastening elements, and with thecover pan extending in the direction away from the central axis up toand beyond the marginal region of the cover, enables a reliableattachment despite the parts that are used being extremely simple tomanufacture.

The arrangement in accordance with which the cover pan extends up to theouter circumference of the edge region of the cover and continues therein a flange which contacts the marginal region of the cover from theoutside in the direction towards the central axis brings about acentering of the generator carrier in the cover without having to takefurther measures.

The arrangement in accordance with which the marginal region of thecover has at least one rib projecting inwardly towards the central axiswith a complementary recess of the wall part lying opposite to the ribin the direction of the central axis in such a way that the generatorcarrier is held axially in both directions after the connection to thecover pan permits, after assembly, first the transport and then theinstallation of the finish assembled arrangement. No further measureshave to be taken in order to keep the arrangement together. Moreover,the arrangement holds the cover so firmly in connection with the gasgenerator in the installed arrangement that it remains reliably attachedthereto even when the gas generator is ignited.

The arrangement in accordance with which the flange extends in thedirection towards the base of the cover beyond the rib ensures, ontriggering of the gas generator, that the marginal region of the cover,which is for example formed from a resilient plastic or from a plasticwhich softens under the heat of the hot gases escaping from the gasgenerator, cannot bulge outwardly in the surrounded region even underhigh gas pressure, whereby the opening region of the gas bag is inparticular particularly safely clamped and a reliable seal issimultaneously obtained.

The arrangement in accordance with which axial slots are provided in thewall of the cover in such a way that the generator carrier can be slidaxially into place between the axial slots from the outside by resilientspreading of the marginal region of the cover simplifies theinstallation.

The arrangement in accordance with which, with a rectangularcross-section of the marginal region of the cover and the wall part, thecorner regions are differentially curved, so that a space is providedfor receiving the turned over folds which are formed on laying of thegas bag onto the wall part, reduces the force that is required duringinstallation and simultaneously counteracts tearing of the gas bag, inparticular in the region of the turned over folds.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in the following by way of exampleand with reference to the drawing in which are shown:

FIG. 1 a cross-section through an airbag arrangement in accordance withthe invention with a somewhat different embodiment being shown to theleft of the central axis 29 from that at the right, and with the overallarrangement being rotationally symmetrical relative to the central axis29,

FIG. 2 a corresponding sectional view of a further advantageousembodiment in accordance with the invention,

FIG. 3 a corresponding schematic section of another embodiment inaccordance with the invention,

FIG. 4 a corresponding schematic section shown only to the left of thecentral axis 29 of an embodiment of the invention having a fusedconnection,

FIG. 5 a perspective partial view of a generator carrier in accordancewith the invention which can be used for the manufacture of the fusedconnection of FIG. 4,

FIG. 6 a section from the region to the right of the central axis 29 ofFIG. 4 during the manufacture of the fused connection by means of a toolin accordance with the invention,

FIG. 7 an enlarged partial sectional view of an embodiment of an airbagarrangement in accordance with the present invention in the region ofthe connection of the generator carrier to the cover,

FIG. 8a a corresponding view to a reduced scale without the cover andthe gas bag,

FIG. 8b a plan view of the article shown,

FIG. 8c a corresponding side view,

FIG. 8d a partly cut away perspective view of the article shown in FIGS.8a to 8c,

FIG. 9 an enlarged partial sectional view analogous to FIG. 7 of afurther embodiment of the present invention,

FIG. 10a a corresponding view to a reduced scale without the cover andthe gas bag,

FIG. 10b a plan view of the article shown,

FIG. 10c a corresponding side view,

FIG. 10d a partly broken away perspective view of the part shown inFIGS. 10a to 10c,

FIG. 11 a further embodiment of an airbag arrangement in accordance withthe invention in section to the left of the central axis and in a sideview to the right of the central axis,

FIG. 12 an enlarged illustration of the region XII in FIG. 11,

FIG. 13 a plan view of the airbag arrangement of FIG. 11, and

FIG. 14 a schematic section of the airbag arrangement of FIG. 11 alongthe line XIV--XIV from which the position of a space in the cornerregions provided for receiving the folds of the gas bag formed duringturning it over is evident, with the parts of the gas bag within thewall part having been omitted for the sake of simplification of thedrawing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In accordance with FIG. 1 a folded up gas bag 13 is provided in apot-like cover 14 having a flat base 15 and a substantiallyright-cylindrical wall 30, with the central axis 29 corresponding to thecylinder axis. The closed end 31 of the gas bag is located directlyopposite to the base 15 whereas an opening 17 provided at the oppositeend accommodates a generator carrier 12. Radially inwardly the generatorcarrier 12 in turn has a receiving opening 32 for a gas generator 11which is inserted and secured there. The gas generator 11 is ofright-cylindrical shape and rotationally symmetrically arranged to thecentral axis 29. It has gas outlet openings 28 which are distributedaround the circumference above the point of connection to the generatorcarrier 12. Hot gas jets emerge radially from the gas outlet openingswhen triggered.

It is important that a right-cylindrical edge region or collar 18 at theopening of the gas bag, with the central axis 29 as the cylinder axis,adjoins the region 33 of the gas sack disposed as folds 13' extendingperpendicular to the central axis 29. The edge region or collar 18 atthe opening contacts the inner wall 19 of the marginal region 16 of thecover of the wall 30 remote from the base 15.

In accordance with the invention the generator carrier 12 consists of aframe part 27 which surrounds the gas generator 11 and which representsa frame ring with the illustrated circularly symmetrical arrangementrelative to the central axis 29. It has a radially outer wall part 20bent down in the direction away from the base 15. In the illustratedembodiment the wall part 20 has essentially the form of a rightcylinder. The diameter of the wall part 20 is so selected that its outerwall contacts the inner side of the marginal region 18 at the opening.This corresponds to a preferred arrangement in which the generatrices ofthe marginal region 18 at the opening and of the wall part 20respectively extend parallel to one another. A further preferredarrangement results when the generatrices converge somewhat in thedirection towards the base 15 of the cover 14.

The marginal region 18 of the gas bag 13 at the opening extends up tothe end edge 21 of the marginal regions 16 of the cover remote from thebase 15 and is there folded around the end edge towards the outside. Inthe embodiment shown to the right of the central axis 29 in FIG. 1 theturned around edge region 18' is practically only located in the regionof the end edge 21. In contrast, in the embodiment shown to the left ofthe central axis 29 the turned around marginal region 18' extends over aconsiderable part of the outer wall 22 of the marginal region 16 of thecover in the direction back to the base 15.

The wall part 20 of the generator carrier 12 has a row of bendable clips23 at its end remote from the base 15 with the clips preferably beingformed in one piece with the wall part. The bendable clips 23 havefastener means at a spacing from the end edge 21 in the form of flatregions 25 which can be deformed in accordance with the through-joiningmethod.

In FIG. 1 the bendable clip 23 and the fastener regions 25 areillustrated both in the starting position prior to being bent round andalso in the finished installed position where a force clamp 25' of athrough-set joint is generated by rivet-like deformation of the regions25 and flowing together of these regions with the wall part 20 which issubjected to complementary deformation at 26.

In the region of each fastener clip 23 there is located, in the marginalregion 16 of the cover, a radial securing bore 24 having a diameteradapted to the diameter of the force clamp 25'.

The manufacture and installation of the described airbag arrangementtakes place as follows:

The gas bag 13 is manufactured from a folded together part 33 and amarginal region or collar 18 at the opening and can optionally bedelivered as a prefinished part.

The further parts of the arrangement, namely the generator 11, thegenerator carrier 12 and the cover 14 can be separately manufacturedwith the cover 14 and the generator 11 assembled to the generatorcarrier 12 initially representing separate components.

Thereafter the gas bag 13 is first introduced in the folded togetherform into the internal space of the cover 14 in the manner shown in FIG.1, with the edge region 18 at the opening being folded outwardly aroundthe end edge 21 and thereby coming into contact with the inner wall 19and, in the embodiment to the left of the central axis also with theouter wall 22 of the marginal region 16 of the cover.

The generator carrier which has already been assembled to the gasgenerator 11 or is formed in one piece with it is now pushed into placeaxially from the side opposite to the base 15 and the gas bag 13, withthe wall part 20 sliding along the inner wall of the marginal region ofthe gas bag 13 at the opening until the position evident from FIG. 1 hasbeen reached.

The bending clips 23 are now bent around the end edge 21 in theclockwise sense to the left of the central axis 29 and in thecounter-clockwise sense to the right of the central axis 29 by means ofa suitable non-illustrated tool, with the regions 25 being formed andbeing driven through the fastening bores 24, boring through the marginalregion 18 of the opening and being riveted to the wall part 20 throughformation of the complementary recesses 26. For this process a suitabletool can be provided which effects all bends and joining processes atthe same time.

After connection of the deformed regions 25' to the wall part 20 by theformation of undercut recesses 26 the marginal region 18 at the openingis clamped to the wall part 20 and to the marginal region 16 of thecover in pressure-tight manner so that a reliable mounting of the gassack 13 in the region of its opening 17 is ensured on ignition of thegas generator 11, and subsequent inflation of the gas bag 13 whilebreaking open the base 15 of the cover 14.

The step 27' in the frame ring 27 which is formed in the embodiment ofFIG. 1 as a ring step which is conically broadened towards the base 15is of particular importance. It lies radially opposite to the gas outletbores 28. In this manner the hot gases which emerge out of the gasoutlet bores 28 in the direction of the dashed arrows in FIG. 1 firstreach the ring step 27' where they are deflected substantially in thedirection towards the base 15 and thereby inflate the gas bag 13. Inthis manner the hot gases are largely kept away from the radiallyinwardly exposed and substantially stationary region 34 of the gas bag13.

As a result of the design in accordance with the invention the generatorcarrier 12 can be shaped largely in any desired form providing only thatit has the basic frame form which can be seen from FIG. 1. More than onegenerator 11 can also be secured to a generator carrier 12.

A substantially ring-like cover region 35 can also be provided aroundthe base of the pot-like cover 14 which covers over the components lyingbehind it.

In the following figures the same reference numerals are used todesignate components which have counter-parts in FIG. 1.

In the embodiment of FIG. 2 a clamping channel 36 which extends allaround the axis 29 and has an essentially U-shaped cross-section adjoinsthe wall part 20 of the generator carrier 12 at the outside, with theclamping channel being open in the direction towards the base 15 of thecover 14. Snap hooks 37 are stamped and bent outwardly out of the wallpart 20 belonging to the clamping channel 36 at specific intervals inthe circumferential direction and engage in complementary snap recesses39 at the inner side of the marginal region 16 of the cover, and indeedin such a way that the free end edge 44 of the snap hooks 37 engages inbarb-like manner into the snap recess and thus prevents the generatorcarrier being drawn out downwardly from the position of FIG. 2.

The marginal region 18 of the gas bag 13 at the opening extends betweenthe snap hook 37 and the snap recesses 39 in just the same way asbetween the wall part 20 and the marginal region 16 of the cover. At thefree end edge 44 of the snap hooks 37 the gas bag is particularlyeffectively held during inflation.

In the embodiment of FIG. 3 the wall part 20 has stamped out apertures49 at the positions where the snap hooks 37 are provided in theembodiment of FIG. 2. Snap springs 38 are inserted into these apertures49 and extend between a bearing groove 45 of the generator carrier 12and the lower edge of the snap recess 39 in FIG. 3. In analogous mannerto the snap hooks 37 of FIG. 2 the snap springs prevent the generatorcarrier 12 being extracted downwardly in FIG. 3 out of the marginalregion 16 of the cover which surrounds it.

FIG. 5 shows in a perspective partial view a generator carrier 12 suchas is used in the embodiment of FIGS. 4 and 6. The clamping channel 36'is here interrupted at intervals by apertures 40, however the individualremaining U-shaped regions 36" still remain connected by narrow webs 46.

If a clamping channel 36 of this kind is set in place in accordance withFIG. 6 onto the end of the marginal region 16 remote from the base 15while trapping the marginal regions 18, 18' of the gas bag 13 and ifthis arrangement is heated up by the correspondingly shaped die 42 of aheatable tool 41 then the thermoplastic material of the marginal region16 of the cover melts in the region of the clamping channel 36 in such away that it flows, while expanding the parts of the marginal region 18of the gas sack 13 surrounding the marginal region 16, into theapertures 40 and largely fills out the space predetermined by the die42.

The shaped opening of the die 42 extends sideways up to and beyond theinner and outer walls 50, 51 of the marginal region of the cover,whereby the clamped marginal region 18, 18' of the gas bag 13 forms astep 47 to each side in the region of the apertures 40, with an archedregion 48 which is approximately semicircular in cross-section extendingbetween the steps 47. As the steps 47 extend laterally beyond the narrowwebs 46 in the region of the apertures 40 a particularly good retentionof the gas sack 13 in this region is ensured during the inflation.

In the further development of the above-described airbag arrangementsfurther advantageous embodiments are now possible which will bedescribed with reference to the FIGS. 7 to 13.

In FIG. 7 there is shown a section of an airbag arrangement which can beformed essentially as described with reference to FIG. 2, with aclamping channel having a substantially U-shaped cross-section adjoiningthe generator carrier 12 and extending around the axis. The clampingchannel 36 is open in the direction towards the base 15 of the cover 14which is not shown in FIG. 7 and has a base 20" at the oppositelydisposed side. Projections in the form of V-shaped webs 63 which projectinto the clamping channel at specific intervals in the circumferentialdirection are formed from the inner wall part 20 belonging to theclamping channel 36 and are for example cut out, pressed out or bent outby coining, and these projections engage into complementary recesses 58at the inner side of the marginal region 16 of the cover, and indeed insuch a way that the cover 14 is anchored by the webs in order in thisway to prevent the gas generator 12 being pulled out of position.

In accordance with FIGS. 8a-d provision is made in this respect for theprojections 63 to be arranged over the entire length of the clampingchannel 36 and indeed preferably directly following one another. Theirdepth corresponds approximately to the width of the clamping channel 36.

When the generator carrier 12 is rectangular and the corner regions arerounded off the manufacture is facilitated in that no material ispressed out into the corner regions which does not significantly impairthe anchorage.

Although the webs 63 in FIGS. 7 and 8 are shown provided at the innerwall 20 of the clamping channel 36 it is straightforwardly possible toprovide webs in place of them or in addition to them at the outer wall20' of the clamping channel 36.

Opposite to the web 63 there is provided recesses 58 in the marginalregion 16 of the cover which can be pressed by the webs 63 into thematerial of the cover 14 which for example consists of plastic. Themarginal region 18 of the gas bag 13 at the opening which is laid aroundthe end edge 21 is held tight particularly effectively in this manner.

The manufacture of the gas bag can again take place in the previouslydescribed manner in that the gas bag 13 consisting of a folded togetherpart 33 with the marginal region 18 at the opening and the further partsof the arrangement, namely the generator 11, the generator carrier 12and the cover 14 are, if necessary first separately manufactured, withthe cover 14 and the generator 11 which is assembled to the generatorcarrier 12 initially representing separate components.

In this case the gas bag 13 can be subsequently introduced in foldedtogether form into the inner space of the cover 14 in the manner forexample shown from FIG. 1, with the marginal region 18 at the openingbeing folded around the end edge 21 and thereby coming into contact withthe inner wall 19.

The generator carrier 12 which has already been assembled to the gasgenerator 11, or is formed in one piece therewith, is now insertedaxially from the side remote from the base 15 and the gas bag 13, withthe wall part 20 sliding along the inner wall of the marginal region ofthe gas bag 13 at the opening until the desired position has beenreached.

Provision can, on the one hand, be made for the webs 63 to have beenformed in the generator carrier 12 prior to the assembly of thecomponents. In this arrangement the clamping channel is bent open and isonly bent together into its final shape with a suitable tool afterhaving been mounted on the marginal region 16 of the cover whiletrapping the marginal region at the opening 18. The webs 63 push intothe marginal region 16 of the cover and press in the recesses 58. Afurther possibility consists of first coining the webs when thegenerator carrier 12 already contacts the marginal region 16 of thecover while trapping the marginal region 18 at the opening.

The marginal region at the opening is now connected in pressure-tightmanner to the wall part 20 and to the marginal region 16 of the cover sothat a reliable retention of the gas bag in the region of its opening 17is ensured on triggering of the gas generator 11 and the subsequentinflation of the gas bag 13 while breaking open the base 15 of the cover14.

In the embodiment of FIG. 9 which is similar to that of FIG. 2 aclamping channel 36 within an essentially U-shaped cross-sectionextending outwardly around the axis again adjoins the generator carrier12. The clamping channel 36 is open towards the base 15 of the cover 14which is not shown in FIG. 9 and has a base 20" at the oppositelydisposed side. In this arrangement the clamping channel 36 is providedat the inner wall with a first projection in the form of the rib 61extending along the clamping channel 36 and preferably substantiallyaround the latter. The rib 61 can for example be formed by a deepdrawing process while forming a recess 64 at the opposite side of theclamping channel wall 20 and can engage with a groove 60 formed at theoppositely disposed cover wall 19. Furthermore, the oppositely disposedouter wall 20' of the clamping channel 36 has a second projection 62 inthe form of its edge which is bent down towards the opening, with theopening of the clamping channel 36 being partially covered over as canbe particularly clearly seen from FIG. 10 and with the bent over edge 62engaging with a recess 59 formed in the oppositely disposed outer wallof the marginal region 16 of the cover.

As can be further deduced from FIG. 10 both projections 61, 62 extendover a considerable part of the length of the clamping channel 36. Theengagement between the projections 61, 62 and the respective oppositelydisposed recesses 60, 59 in the marginal region 16 of the cover 14brings about an anchorage in such a way that the extraction of thegenerator 12 out of its position is prevented.

With a rectangular generator carrier with rounded corner regions themanufacture is in turn facilitated when no material is pressed out inthe corner regions which does not significantly impair the anchorage.The marginal region 18 of the gas bag 13 at the opening extends betweenthe projections 61 and 62 and the respective oppositely disposedrecesses 60 and 59 in the marginal region 16 of the cover in the sameway as between the wall parts 20 and 20' and the marginal region 16 ofthe cover, so that the gas bag 13 is particularly effectively heldduring inflation.

In this case the manufacture of the gas bag 13 and of the remainingparts, namely the generator 11, the generator carrier 12 and the cover14 can, if necessary, also take place separately.

Thereafter the gas bag 13 is first introduced in folded together forminto the inner space of the cover 14 in the previously described manner,with the marginal region 18 at the opening being turned around the endedge 21 and thereby coming into contact with the inner wall 19 and theouter wall 22 of the marginal region 16 of the cover. The generatorcarrier 12 which has already been assembled to the gas generator 11, orwhich is formed in one piece therewith, is now axially pushed into placefrom the side remote from the base 15 and the gas bag 13, with the wallpart 20 sliding along the inner wall of the marginal region 18 of thegas bag 13 at the opening until the desired position is achieved.

During this provision can, on the one hand, be made for the rib 61 andthe bent over edge 62 to have already been formed prior to the joiningtogether of the components, with the clamping channel first being bentopen and thus broadened and being squashed together with a suitable toolonto the marginal region 16 of the cover only after it has been mountedonto the marginal region 16 of the cover. A further possibility is tofirst deep draw the projections when the generator carrier already lieson the marginal region of the cover.

After the engagement of the projections 61 and/or 62 with the recessesprovided in the wall part 20 the marginal region 18 at the opening isclamped in pressure-tight manner to the wall part 20 and to the marginalregion 16 of the cover, so that a reliable retention of the gas bag 13is ensured in the region of its opening 17 on triggering of the gasgenerator 11 and subsequent inflation of the gas bag 13 while breakingopen the base 15 of the cover 14.

A preferred airbag arrangement in accordance with the present inventionwhich is particularly suited for passenger seats will be explained withreference to the FIGS. 11 to 14.

In accordance with this embodiment the folded together gas bag 13 isprovided in the pot-like cover 14 with the flat base 15 and the wall 30comprising a rectangle with rounded corners having the central axis 29.The closed end 31 of the gas bag 13 is located directly opposite to thebase 15, whereas its opening 17 provided at the oppositely disposed endreceives the gas generator 11 which is secured in accordance with FIG.13 into a circular receiving opening 32 of a square plate 65. The gasgenerator 11 is rotationally symmetrically arranged around the centralaxis 29 and has gas outlet openings 28 distributed around the peripheryabove the connection to the generator carrier 12 with hot gas jetsemerging radially from the gas outlet openings 28 when triggered.

The region 33 of the gas bag 13 having folds 13' extending perpendicularto the central axis 29 is joined by the marginal region 18 at theopening in the direction away from the base 15. The marginal region 18at the opening generally contacts the inner wall 19 of the wall 30 ofthe marginal region 16 of the cover. A plurality of axially extendingslots 56 are provided in the wall 30 which preferably lie diametricallyopposite to each other and which extend axially from the end edge of themarginal region 16 of the cover in the direction towards the base 15.The corners of the marginal region 16 of the cover are more stronglycurved in accordance with FIG. 14 than those of the wall part 20 wherebycorner spaces 55 are formed. The turn-over folds 18"' of the gas bagwhich arise in the axial direction during the turning over of themarginal region 18 at the opening outwardly around the planar part 18",which extends around the generator 11 perpendicular to the central axis29, are accommodated in these corner spaces 55.

The generator carrier 12 consists of the frame part 27 which surroundsthe gas generator 11 and which is rectangular in the illustratedembodiment and overlaps the plate 65 at the inside and of the one-pieceouter wall part 20 which is bent in the direction towards the base 15,in particular by deep drawing.

At the side of the frame part 27 remote from the base 15 of the cover 14there is provided a cover pan 54 having a planar base 54' and a flange54" bent over at right angles in the direction of the base 15 of thecover 14. The base 54' has a central opening for receiving the generatorcarrier 12 and is placed onto the frame part 27 and connected to thelatter via fastener elements 57 such as screws, bolts or the like whileclamping the marginal region 18 at the opening which is guided along thewall 20 and between the latter and the wall 19 of the marginal region 16of the cover. In this arrangement the flange 54" of the cover pan 54engages around the marginal region 16 of the cover and contacts it fromthe outside. In this way a bulging out of the marginal region 16 of thecover in the region of the flange 54" is avoided.

In accordance with the invention the marginal region 16 of the cover atthe end region remote from the base 15 of the cover 14 has an inwardlybroadened rib 52 which stands in engagement with a complementary recessof the wall part 20 in such a way that the generator carrier 12 is heldaxially in both directions while clamping the marginal region 18 at theopening following the connection with the cover pan 54. The boundary 52'of the rib 52 of the recess 53 remote from the base 54' therebyexpediently extends obliquely to the central axis 29. The boundary ofthe rib 52 remote from the base is flush with the marginal region 16 ofthe cover and lies together with the latter against the base 54'. Theboundary 52" of the rib 52 or of the recess 53 facing the central axis29 extends in the axial direction.

The individual parts can be assembled in different ways. Preferably thegenerator carrier 12 is first introduced into the marginal region 18 ofthe gas bag 13 at the opening in such a way that the marginal region 18at the opening extends along the wall part 20 and then along the planarframe part 27. The cover 14 is then pushed axially onto the wall part20, with the marginal region 16 at the cover being resiliently spreadapart between the axial slots 56 by the wall part 20 until theprojections 52 which slide along the wall part 20 and the gas bag 13 cansnap into the recesses 53. At the same time the turn-over folds 18"'enter into the corner spaces 55 provided therefor.

The gas generator 11 with the plate 65 and the cover pan 54 are securedto the frame part 27 by fastener elements 57 from the base 15 whileclamping the planar part 18" of the marginal region 18 at the openingbetween the frame part 27 and the base 54'. The flange 54" of the coverpan 54 engages around the marginal region 16 of the cover. The fastenerelements 57 which axially clamp together the frame part 27, the base 54'and the plate 65 lying thereon, ensure that the generator 11 and alsothe generator carrier 12 and the cover pan 54 are reliably held togetheraxially in both directions.

In this manner the marginal region 16 of the cover is surrounded inreinforcing manner by the flange 54" so that the marginal region 16 ofthe cover cannot bulge into the region surrounded by the flange 54" andso that the marginal region 18 at the opening remains securely clampedthere and between the plate-like frame part 54" on triggering of the gasgenerator 11 and the subsequent expansion of the gas bag 13 whilebreaking open the base 15 of the cover 14.

The quadratic or circular opening 17 of the gas bag 13 surrounds, inaccordance with FIG. 11, the preferably right-cylindrical outer wall ofthe generator 11 or lies opposite to it at a small radial spacing. Theplanar part 18" of the marginal region 18 which directly surrounds theopening 17 and extends outwardly up to the end of the planar plate-likeframe part 27 is flat after being clamped between the frame part 27 andthe base 54' so that a mechanically firm and gas-tight connection isprovided there. The folds 18" which result on laying the marginal region18 of the opening into the axial direction along the wall part 20 areaccommodated as already described above with reference to FIG. 14 in thecorner spaces 55 which are provided for this purpose.

What is claimed is:
 1. An airbag assembly for motor vehiclescomprising:a pot-shaped cover having a base portion and a wall portionextending away from the base and a marginal region of the cover wallportion including an end thereof remote from the base; at least one gasgenerator; a generator carrier having a wall portion extendingsubstantially parallel to the cover wall portion; a folded-up gas bag inthe cover for being expanded by gas from the gas generator and breakingopen the cover base portion and including a gas bag opening forreceiving the gas generator and having a marginal region free of beadsand inserts extending around the bag opening with the bag marginalregion clamped securely between the cover wall portion marginal regionand the generator carrier wall portion, wherein a clamping channel whichis open towards the marginal region of the cover wall portion andcomplementary thereto is provided around the wall portion of thegenerator carrier and is axially mounted onto the marginal region of thecover wall portion with the marginal region of the gas bag beinginserted therebetween, and one of a (1) snap engagement provided betweenthe marginal region of the cover wall portion, the marginal region ofthe gas bag and the clamping channel including one of snap hooks andsnap springs which are distributed around the clamping channel andcooperating with complementary snap recesses formed in the wall of themarginal region of the cover wall portion to provide the snapengagement, and (2) a fused connection provided between the marginalregion of the cover wall portion, the marginal region of the gas bag andthe clamping channel and including apertures formed at intervals in theclamping channel for receiving flowed molten material of the marginalregion of the cover wall portion during manufacture of the fusedconnection with the marginal region of the gas bag being turned aroundthe end of the marginal region of the cover and being gripped by thefused connection.
 2. The assembly of claim 1 wherein the cover wallportion marginal region has an inner wall surface and an outer wallsurface and the marginal region of the bag at the opening is laid aroundthe end of the marginal region of the cover wall portion and the laidaround bag marginal region is held at the outer wall surface of themarginal region of the cover wall portion.
 3. The assembly of claim 1wherein the clamping channel includes an inner wall and an outer wall ofthe channel with one of the channel walls having at least one projectionand the cover wall portion marginal region has at least onecorresponding recess for cooperating with the projection of the clampingchannel one wall to capture the bag marginal region in the clampingchannel wherein the at least one projection is one of: (1) formed by adeep drawing process with a projection extending from one side of theclamping channel one wall and a clamping channel wall recess is formedat the other side of the one wall opposite to the projection; (2) formedas a rib extending along the clamping channel and the at least onerecess of the cover wall portion marginal region is a groove extendingin the clamping channel; (3) formed by a margin of the outer wall of theclamping channel with the inner wall and outer wall cooperating todefine a channel opening therebetween and the outer wall margin beingbent down towards the opening of the clamping channel and the at leastone recess of the cover wall portion marginal region is a groove formedin the oppositely disposed marginal region of the cover wall portion;and (4) formed by webs which are formed from the one wall of theclamping channel and extend alongside each other along the clampingchannel.
 4. An airbag assembly for motor vehicles comprising:apot-shaped cover having a base portion and a wall portion extending awayfrom the base and a marginal region of the cover wall portion includingan end thereof remove from the base; at least one gas generator havinggas outlet openings; a generator carrier having a wall portion extendingsubstantially parallel to the cover wall portion; a folded-up gas bag inthe cover for being expanded by gas from the gas generator and breakingopen the cover base portion and including a gas bag opening forreceiving the gas generator and having a marginal region free of beadsand inserts extending around the bag opening with the bag marginalregion clamped securely between the cover wall portion marginal regionand the generator carrier wall portion, wherein the generator carrierhas a frame part including inner and outer sides with the gas generatorsupported at the inner side of the frame and with the carrier wallportion formed at the frame outer side and the frame part has one of astep and a chamfered area, substantially aligned with the level of thegas generator outlet openings.
 5. An airbag assembly for motor vehiclescomprising:a pot-shaped cover having a base portion and a central axisof the cover extending through the base and a wall portion of the coverextending away from the base about the cover axis and a marginal regionof the cover wall portion including an end thereof remote from the base;at least one gas generator; a generator carrier having a wall portionextending substantially parallel to the cover wall portion; a folded-upgas bag in the cover for being expanded by gas from the gas generatorand breaking open the cover base portion and including a gas bag openingfor receiving the gas generator and having a marginal region free ofbeads and inserts extending around the bag opening with the bag marginalregion clamped securely between the cover wall portion marginal regionand the generator carrier wall portion, wherein the generator carrierhas a frame part including inner and outer sides with the gas generatorsupported at the inner side of the frame part and with the carrier wallportion formed at the frame part outer side and the frame part is formedas a substantially planar plate connected to the wall portion of thegenerator carrier and having an opening for receiving the generator,there being a planar cover pan having an opening for receiving thegenerator and extending from the opening in a direction away from thecover axis beyond the marginal region of the cover wall portion andsecured against the surface of the planar plate facing away from thecover base with the bag marginal region being fixedly clamped betweenthe planar plate and the planar cover pan.
 6. Arrangement in accordancewith claim 5, wherein the cover pan includes a flange which contacts theouter side of the marginal region of the cover wall portion distal fromthe central axis.
 7. Arrangement in accordance with claim 5 wherein themarginal region of the cover has at least one rib projecting inwardly inthe direction towards the central axis and the carrier wall portionincludes a complementary recess lying opposite to the rib in thedirection towards the central axis so that the generator carrier is heldagainst movement axially.
 8. Airbag arrangement in accordance with claim7 wherein the flange extends in the direction towards the base portionof the cover up to and beyond the rib.
 9. Airbag arrangement inaccordance with claim 5 wherein axial slots are provided in the wallportion of the cover to allow the generator carrier to be slid axiallyfrom the outside towards the cover base portion between the axial slotswith the axial sliding of the carrier causing resilient spreading of themarginal region of the cover wall portion.
 10. The assembly of claim 5wherein the marginal region of the cover wall portion and the wallportion of the carrier extend around the cover axis with a substantiallyrectangular cross-sectional configuration and each form corner regionswith the corner regions of the cover wall portion being adjacent thecorner regions of the carrier wall portion with the adjacent cornerregions of the cover and carrier wall portions being of differentcurvature in such a way that a space is provided for receiving turn-overfolds of the bag formed by contact of the gas bag against the wallportion of the carrier.
 11. An airbag assembly for motor vehiclescomprising:a pot-shaped cover having a base portion and a wall portionextending away from the base and a marginal region of the cover wallportion including an end thereof remote from the base portion; at leastone gas generator; a generator carrier having a wall portion extendingsubstantially parallel to the cover wall portion and having an endremote from the cover base; a folded-up gas bag in the cover for beingexpanded by the gas from the gas generator and breaking open the coverbase portion and including a gas bag opening for receiving the gasgenerator and having a marginal region free of beads and insertsextending around the bag opening with the bag marginal region clampedsecurely between the cover wall portion marginal region and thegenerator carrier wall portion, wherein the cover wall portion marginalregion has an inner wall surface and an outer wall surface and themarginal region of the bag at the opening is laid around the end of themarginal region of the cover wall portion and the laid around bagmarginal region is held at the outer wall surface of the marginal regionof the cover wall portion, and the carrier wall portion has bendingclips at the remote end of the carrier wall portion and which can bebent around the end of the cover wall portion and secured in thebent-around state to the marginal region of the cover wall portion. 12.The assembly of claim 11 wherein the carrier wall portion includesrecesses adjacent the carrier remote end, the bendable clips at theremote end of the carrier wall portion include securing means, and thecover wall portion marginal region includes securing bores forcooperating with the clips securing means so that with the clips beingbent around the end of the cover wall marginal region, the clipssecuring means will extend through the bores and form a through-setjoint in the carrier wall portion recesses.